- Intramolecular Geminal and Vicinal Element Effects in Substitution of Simple Bromo(chloro)alkenes by Methoxide and Thiolate Ions. An Example of a Single Step Substitution?
-
Intramolecular element effects kBr/kCl for substitution of geminal bromochloroalkenes BrC(Cl)=C-(Br)Cl (1), BrC(Cl)=CCl2 (2), Me2C=C(Br)Cl (3), and XCH=C(Br)Cl (X = Cl, 4; X = Br, 5), with MeO- and RS- nucleophiles were investigated. 3 did not give substitution, and 4 and 5 gave substitution with MeO- via an initial elimination (to acetylene)-addition route, followed by further reactions. In reactions of 4 with thiolates, geminal element effects of 2-10 were obtained. Formation of RSC(Cl)=C(Cl)Y, Y = SR, Br, is ascribed to an initial halophilic reaction, followed by addition of RSCl to the formed acetylene. Reaction of 2 with MeO- gave a high vicinal element effect, and RS- gave a high geminal element effect. Reaction of 1 with both MeO- and RS- ions gave high (2 orders of magnitude) geminal element effects, which were interpreted as indicating a rate-determining C-X bond cleavage. This is supported by the high kBr/kCl intermolecular element effects (k(1)/k(Cl2C=CCl2) with MeO- and PhCH2S- ions. Mechanistic alternatives based on these observations are discussed.
- Beit-Yannai, Michal,Rappoport, Zvi,Shainyan, Bagrat A.,Danilevich, Yuri S.
-
p. 8049 - 8057
(2007/10/03)
-
- N-BROMOURETHANE IN REACTION WITH TRICHLOROETHYLENE
-
The reaction of N-bromourethane with trichloroethylene leads to the formation of 2-bromo-2,2-dichloro-1,1-di(ethoxycarbonylamino)ethane.A reaction mechanism including a series of consecutive transformations is proposed: Disproportionation of the N-bromourethane to N,N-dibromourethane and urethane; reaction of the N,N-dibromourethane with trichloroethylene with the formation of N-(2-bromo-2,2-dichloroethylidene)ethoxycarbonylamine; addition of urethane to the latter with the formation of 2-bromo-2,2-dichloro-1,1-di(ethoxycarbonylamino)ethane.
- Drozdova, T. I.,Mirskova, A. N.,Levkovkaya, G. G.
-
p. 862 - 865
(2007/10/02)
-
- SYNTHESIS AND PROPERTIES OF N-(2,2-DICHLORO-2-BROMOETHYLIDENE)BENZENESULFONAMIDE FROM N,N-DIBROMOBENZENESULFONAMIDE AND TRICHLOROETHENE
-
The free-radical reaction of N,N-dibromobenzenesulfonamide with trichloroethene leads to the production of the previously unknown highly reactive N-(2,2-dichloro-2-bromoethylidene)benzenesulfonamide.The reaction of N-(2,2-dichloro-2-bromoethylidene)benzenesulfonamide with benzenesulfonamide or water gave N-(2,2-dichloro-2-bromo-1-hydroxyethyl)benzenesulfonamides.
- Drozdova, T. I.,Mirskova, A. N.,Levkovskaya, G. G.,Kalikhman, I. D.,Voronkov, M. G.
-
p. 1116 - 1119
(2007/10/02)
-
- Bromination of side chain of m-phenoxytoluene
-
A process for brominating m-phenoxytoluene with a polyhaloethane having the formula STR1 wherein W and Z respectively represent Cl or Br and X and Y respectively represent Cl, Br or H in a liquid phase.
- -
-
-